THE PRESENT INVENTION relates to a safety arrangement, and more particularly relates to a safety arrangement in a motor vehicle such as a motor car.
It has been proposed previously to provide safety managements in a motor car, which are adapted to be activated in the event that an accident should occur, with the safety arrangements incorporating devices mounted on the seat of the motor vehicle.
For example it has been proposed to provide an inflatable air-bag, initially stored within the back-rest of a vehicle seat, the air-bag being adapted to occupy a position between the main part of the torso of the occupant of the seat and the side of the vehicle in the event that an accident should occur. Also, it has been proposed to provide a pre-tensioner mounted directly on the seat of a motor vehicle, the pre-tensioner being adapted to apply tension to a seat belt in the event that an accident should occur, so as to retain the person wearing the seat belt firmly in position in the seat.
It is known that seats may be adjustably mounted in position within a motor vehicle, with the seats sliding forwardly and reawardly along rails mounted on the floor pan of the motor vehicle. A seat can thus be adjusted to a position which is comfortable for the occupant of the seat. In such a situation it has been proposed to provide an electrical connection to a safety device mounted on the seat in the form of a wire or cable which extends from the seat to the main wiring loom of the vehicle. This wire or cable is generally located beneath the seat. The cable can become worn or damaged if the position of the seat is adjusted many times, and also the wire or cable may be become snagged or damaged if objects are placed under the seat.
There is an increasing demand for vehicles in which seats can be completely removed from the vehicle in order to enhance the space available for transporting items within the vehicle. It has previously proved impracticable to provide a safety device in such a seat which requires electric power or other signals from the main wiring loom of the vehicle. It would not be appropriate to provide a wire which would need to be plugged in when a seat is replaced in a vehicle, since many owners of vehicles may not connect such plugs when installing seats in vehicles.
The present invention seeks to provide an improved safety arrangement in which electric power and/or control signals to activate a safety device can be passed reliably to a seat which is movably mounted within a motor vehicle, or which may be completely removed from the motor vehicle.
According to this invention there is provided a safety arrangement for use in in a motor vehicle, the safety arrangement comprising rail means provided on the floor of the vehicle and a vehicle seat movably mounted on the rail means, the rail being associated with a plurality of primary coils at positions spaced along the length of the rail, said primary coils acting as transmitting antennas and the seat being associated with one or more receiving antennas, the or each receiving antenna being in the form of at least one secondary electromagnetic coil, the arrangement further comprising means to supply a signal to at least one transmitting antenna to transfer power to at least one receiving antenna, there being a safety device mounted in or on the seat, actuating means being provided to use the power transferred to the said receiving antenna to actuate the said safety device, the arrangement incorporating selector means adapted to select the primary coil or coils which receive power to be transferred to the secondary coil or coils, there being a seat position sensor adapted to sense the position of the or each seat mounted on the rail, and to control the selector means in dependence upon the sensed position of the or each seat to supply the power to one or more primary coils adjacent the or each seat.
In a preferred embodiment the transmitting antennas that are associated with the rail extend immediately adjacent the rail or, in a most preferred embodiment, are mounted in or on the rail. Also it is preferred that the one or more receiving antennas associated with the seat are mounted on a part of the seat immediately adjacent the rail, with the antenna or antennas preferably being mounted on part of the seat that engages the rail.
The primary and secondary coils may be each wound about a vertical axis.
Conveniently the signal supplied to the primary coil or coils has a frequency of substantially 20 kHz.
Preferably the or each primary coil is of elongate form, the longitudinal axis of the coil being aligned with the axis of the rail.
Preferably the or each secondary coil is connected to the actuating means via rectifier means.
Advantageously a plurality of secondary coils are provided, each of the secondary coils being connected to a respective rectifier means, the output of the rectifier means being connected in parallel to the actuating means.
Conveniently three secondary coils are provided, and two secondary coils are located adjacent each other, with the third secondary coil over-lapping the two adjacent secondary coils.
Preferably the length of each of said three coils is approximately one-half the length of the seat.
Advantageously each coil is provided with a ferrite core.
Conveniently a capacitor is provided in the seat, power from the or each receiving antenna being used to charge the capacitor, means being provided to cause the capacitor to discharge to actuate the safety device in response to an accident being detected.
Preferably the means to cause the discharge of the capacitor comprise a crash sensor and means to transmit a predetermined signal in response to the detection of a crash, the seat being provided with means to receive the signal and means to respond to the received signal to discharge the capacitor to actuate the safety device.
Conveniently the transmitting and receiving means are adapted to transmit the signal via said transmitting and receiving antennas.
In an alternative embodiment a crash sensor is provided adapted to activate said signal supplying means in response to the detection of a crash.
Preferably the vehicle seat which is movably mounted on the rail is mounted for axial movement alone the rail.
Alternatively, or additionally, the vehicle seat which is movably mounted on the rail may be mounted to be removable from the rail.
Preferably means are provided to sense the condition of the seat and to inhibit actuation of the safety device if the seat is in a predetermined condition.
Advantageously the means to sense the condition of the seat are adapted to generate a predetermined signal if the seat is in a folded condition resembling a table to inhibit actuation of the safety device whilst the seat is in that condition.
Conveniently the seat incorporates a safety device which comprises a pyrotechnic charge, and the actuating means comprises a squib to ignite the pyrotechnic charge, the squib being adapted to receive power from the receiving antenna.
The safety device may comprise a pyrotechnic pre-tensioner, or an air bag.